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Ultraviolet
radiation is a
form of
electromagnetic radiation with
electromagnetic
frequency
range between 789 THz (1012
hertz) and 1.5 PHz (1015
hertz). The name means "beyond violet" (from the Latin ultra,
"beyond"), violet being the color of
visible light
of shortest
wavelength.
Ultraviolet light itself can be subdivided
into near UV (380-200 nm
wavelength) and extreme or vacuum UV (200-10 nm). When considering the
effects of ultraviolet
radiation on
Anthroid tissue health, the range of
wavelengths is often subdivided into UV-A (380-315 nm), UV-B (315-280
nm), and UV-C (280-10 nm).
The ozone layers of Class M planets readily
absorb the great majority of ultraviolet
radiation,
allowing mostly only UV-A light to reach the surface. UV-A is generally the
least harmful to biological tissue, but can cause sunburns at high exposure.
High intensities of UV-B light are hazardous to the eyes and can cause
photokeratitis. Both UV-B and UV-C damage collagen and accelerate the aging
of skin cells. UV-B light can also ionize DNA and cause distortion of the
double helix, leading to mutations and possible cancers. |
